The present invention relates generally to telecommunication techniques. More specifically, embodiments of the present invention provide system and method for efficiently allocating network resources based on group policies. In an embodiment, the present invention provides a technique for sharing of resources in a wireless communication system. In particular, the present invention provides to a novel method of allowing the mobile station to utilize the free radio resources that can be shared among groups of users. There are other variations as well.
In a wireless multiple access communication system, the wireless traffic channel resource (e.g., bandwidth and time interval) is shared by the wireless terminals (i.e., mobile units or mobile station) that are connected to the communication system in a particular cell. Efficient allocation of this traffic channel resource is important, as it impacts the utilization of the traffic channel resource and the quality of service perceived by individual wireless terminal users. One such wireless communications system is the Orthogonal Frequency Division Multiplexing (OFDM) based Multiple Access system.
OFDMA is a system in which a plurality of users performs multiple access using OFDM. In a conventional OFDMA data transmission apparatus, frequency division and time division are carried out when multiple access is performed. Also, diversity may be carried out in a frequency division and a time division to improve an error correction capability.
Compared with many other multiplexing schemes, OFDM utilizes a somewhat unique system design approach. It can be thought of as a combination of modulation and multiple access scheme that segments a communications channel in such a way that many users can share it. Whereas TDMA is based on time division and CDMA is based on code division, OFDM is based on frequency division. OFDM is a technique that divides the spectrum into a number of equally spaced tones, and carries a portion of a user's information on each tone. Each of these tones can be thought of as a frequency subcarrier. OFDM can be viewed as a form of frequency division multiplexing (FDM). However, OFDM has an important special property that each tone is orthogonal with every other tone. FDM typically requires frequency guard bands between the frequencies so that they do not interfere with each other. In contrast, OFDM allows the spectrum of each tone to overlap. Since tones under OFDM are orthogonal, they do not interfere with one another. By allowing the tones to overlap, the overall amount of spectrum required is reduced, thereby increasing the channel availability.
The OFDM technique is often considered as a multiple access technique, as an individual tone or groups of tones can be assigned to different users. For example, multiple users share a given bandwidth, thus yielding a system called orthogonal frequency division multiple access, or OFDMA. Each user can be assigned a predetermined number of tones when they have information to send, or alternatively, a user can be assigned a variable number of tones based on the amount of information they have to send. The assignments are controlled by the media access control (MAC) layer, which schedules the resource assignments based on user demand.
To fully benefit from the OFDM technology, it is often important to use effective and efficient mechanisms for resource allocation. Over the past, various conventional resource allocation techniques have been developed. Unfortunately, these conventional techniques have been inadequate as discussed below.
Therefore, it is desirable to have an improved system and method of resource allocation for OFDM systems.